Hundreds of factory workers are feared trapped under the rubble of a nine-storey building that collapsed like a house of cards near Bangladesh's capital, according to survivors and witnesses.

Rescuers dug out 15 bodies and pulled 58 people alive from the debris, but narrow roads leading to the site hampered efforts to bring in cranes to help remove concrete slabs.

Police and firefighters said the building collapsed on Monday a little after midnight while many employees were working the night shift.

The army brought in sniffer dogs and heavy equipment, including cranes, to the site by Monday afternoon.

Anxious relatives joined rescuers searching for survivors in the flattened remains of the building at Palashbari, 30km from Dhaka, which housed a garment factory. 

A massive pile of bricks and concrete slabs is all that remains of the building. Rescuers and relatives stood helplessly on top, some calling for loved ones.

Security officer Abdul Hye said at least 250 people had been working the night shift at Shahriar Fabrics.

Prime Minister Begum Khaleda Zia flew to Palashbari in the afternoon and was visibly shocked at the scale of the destruction.

Police said the collapse was probably triggered by a boiler explosion at the factory. Fire brigade officials said they would investigate further to determine the exact cause.

Shahid Alam, a senior official of the Dhaka Development Authority, said the factory had been built on marshland without planning permission.

Unauthorised building

State Minister for Home Affairs, Lutfuzzaman Babar, visited the scene on Monday and expressed his annoyance over what he said was its unauthorised construction.

The whereabouts of the building's owners was not immediately known.

Anxious residents used mobile phones to try to contact relatives trapped beneath the rubble.

PHOTO CAPTION

Rescue workers search for survivors trapped under a collapsed nine-story building near Dhaka April 11,2005. (Reuters)